The disclosed embodiments relate to a semiconductor device, and more particularly, to a memory device including a delay circuit having gate insulation films with thicknesses different from each other so as to prevent deterioration of characteristics of the delay circuit.
According to advances in semiconductor manufacture technology, various circuits (e.g., metal-oxide semiconductor (MOS) transistors) are formed on an integrated circuit (IC). The IC is used in customer electronics, and helps to ensure optimum operation performance in various application uses. The IC should satisfy reliability requirements for ensuring operation performance for a certain period of time. Phenomena such as negative biased temperature instability (NBTI) or positive biased temperature instability (PBTI) may cause deterioration of the reliability of transistors. Such phenomena may cause a shift in a threshold voltage (Vth) of transistors, and a shift in the threshold voltage (Vth) of transistors may cause deterioration of performance of ICs or a problem in voltage sensitivity.